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When a loose mechanism, a rattling assembly, or a failed return stroke brings your project to a halt, the culprit is almost always an undersized or worn-out compression spring. Whether you are a hobbyist repairing a pen mechanism, an engineer prototyping a sensor housing, or a maker building a custom fixture, finding the exact wire diameter and free length in one listing saves hours of searching. These stainless steel compression springs are sold in packs of 10 and cover wire diameters of 0.4 mm, 0.7 mm, 0.8 mm, and 1.0 mm across a wide range of outer diameters and free lengths.
Each spring is formed from stainless steel wire, offering corrosion resistance suitable for indoor mechanical assemblies, light outdoor enclosures, and humid environments. Wire diameters span 0.4 mm to 1.0 mm (approximately 0.016 in to 0.039 in), outer diameters range from 8 mm to 18 mm (approximately 0.31 in to 0.71 in), and free lengths run from 5 mm to 50 mm (approximately 0.20 in to 1.97 in). Select your exact wire diameter × outer diameter × free length combination from the variant dropdown above.
These small compression springs are well suited for pen and stylus return mechanisms, electronic switch and button assemblies, miniature valve and latch systems, model-making and robotics prototyping, and precision instrument calibration fixtures — anywhere a consistent, repeatable spring force in a compact form factor is required.
| Material | Stainless Steel |
|---|---|
| Wire Diameter | 0.4 mm / 0.7 mm / 0.8 mm / 1.0 mm (see variant options) |
| Outer Diameter (OD) | 8 mm – 18 mm (see variant options) |
| Free Length | 5 mm – 50 mm (see variant options) |
| Spring Type | Compression (closed / ground ends) |
| Coil Direction | See variant options |
| Surface Finish | Natural stainless (no coating) |
| Quantity per Pack | 10 pieces |
| Load Rating | See variant options |
| Operating Temperature | See variant options |
Match three dimensions: wire diameter (affects stiffness and load capacity), outer diameter (must fit inside your bore or pocket with clearance), and free length (must be longer than your required compressed length plus travel). As a rule of thumb, leave at least 0.5 mm clearance between the spring OD and the bore ID. Select your exact combination from the Sizes dropdown above.
Wire diameter directly controls spring rate (stiffness). Thinner wire (0.4 mm) produces a softer spring with lower load capacity — suitable for lightweight mechanisms like pen clips or small switches. Thicker wire (1.0 mm) produces a stiffer spring capable of handling higher loads — better for latches, valves, or heavier return mechanisms. Choose based on the force your application requires.
Yes. Stainless steel provides good resistance to oxidation and moisture compared to carbon steel springs. These are suitable for indoor assemblies, humid environments, and light outdoor enclosures. For fully submerged or highly corrosive (salt spray, chemical) environments, verify the specific stainless alloy grade meets your requirements before use.
The variant names follow the format Wire Diameter × Outer Diameter × Free Length (all in mm). Manufacturing tolerances apply — typically ±0.1 mm on wire diameter and ±0.5 mm on free length for springs in this size range. If your application requires tighter tolerances, please contact us to confirm before ordering.
Yes. The smaller wire diameter variants (0.4 mm and 0.7 mm) are commonly used in button, switch, and contact spring applications on PCBs and in electronic housings. Stainless steel is non-magnetic in most grades, which is beneficial in sensitive electronic environments. Confirm the OD and free length fit your component footprint using the variant dimensions.
Each order of one unit contains 10 pieces of the selected size. All 10 springs in the pack are the same wire diameter, outer diameter, and free length as specified in the variant you select. If you need multiple sizes, add each size as a separate line item to your cart.
Common uses include pen and stylus return mechanisms, push-button and tactile switch assemblies, miniature valve and check-valve springs, model-making and robotics joints, precision instrument calibration fixtures, battery contact springs, and small latch or lock return mechanisms. The wide size range makes them versatile across hobbyist and light industrial DIY projects.
